KVM Kernel Virtualization Machine on Rocky Linux 9: Difference between revisions
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KEEP THIS IN MIND: In the QEMU / KVM world, here's how the networking thing functions: | KEEP THIS IN MIND: In the QEMU / KVM world, here's how the networking thing functions: | ||
* After installing QEMU / KVM, it creates a Virtual Bridge Adapter intended to be used with NAT. Leave this one as is if you want to use it. But if you just want a simple bridge to connect to the rest of your network, keep reading. This Virtual Bridge | *After installing QEMU / KVM, it creates a Virtual Bridge Adapter intended to be used with NAT. Leave this one as is if you want to use it. But if you just want a simple bridge to connect to the rest of your network, keep reading. This Virtual Bridge | ||
Here's the assumption (unlike all the other tutorials there); | Here's the assumption (unlike all the other tutorials there); | ||
* There is an existing Ethernet Adapter on the Host Machine for QEMU / KVM that has been configured with an IP Address, Subnet Mask, IE, everything needed to communicate via a Network. | *There is an existing Ethernet Adapter on the Host Machine for QEMU / KVM that has been configured with an IP Address, Subnet Mask, IE, everything needed to communicate via a Network. | ||
* During the installation for QEMU / KVM, a Virtual Bridge Adapter was automatically configured | *During the installation for QEMU / KVM, a Virtual Bridge Adapter was automatically configured | ||
OK, here's what to do for creating your own Virtual Bridge Adapter to be used for 'bridging' between your existing network and the Virtual Machine; | OK, here's what to do for creating your own Virtual Bridge Adapter to be used for 'bridging' between your existing network and the Virtual Machine; | ||
* Identify Ethernet Adapter and Virtual Bridge to be used, IE, get their names (eth0, enp1s0of0, virbr0, etc.) using these commands: brctl show AND / OR ip link show | *Identify Ethernet Adapter and Virtual Bridge to be used, IE, get their names (eth0, enp1s0of0, virbr0, etc.) using these commands: brctl show AND / OR ip link show | ||
* Disable the ''existing'' Ethernet Adapter (through GUI or command line). Don't delete it as most tutorials would have you do (if needed you can always enable it later instead of re-creating it from scratch) | *Disable the ''existing'' Ethernet Adapter (through GUI or command line). Don't delete it as most tutorials would have you do (if needed you can always enable it later instead of re-creating it from scratch) | ||
** nmcli connection modify WhatEverConnectionName connection.autoconnect "no" | **nmcli connection modify WhatEverConnectionName connection.autoconnect "no" | ||
** ifconfig WhatEverConnectionName down OR ip link set dev WhatEverConnectionName down | **ifconfig WhatEverConnectionName down OR ip link set dev WhatEverConnectionName down | ||
* nmcli connection add type bridge autoconnect yes con-name virbr1 ifname virbr1 | *nmcli connection add type bridge autoconnect yes con-name virbr1 ifname virbr1 | ||
* Other example NMCLI commands; | *Other example NMCLI commands; | ||
** nmcli connection show | **nmcli connection show | ||
** Modify the /etc/NetworkManager/system-connections File? Nope! | **Modify the /etc/NetworkManager/system-connections File? Nope! | ||
*** nmcli connection modify WhatEverConnectionName ipv4.address "WhatEverIPAddress/SubnetMaskNumber" (192.168.1.1/24) | ***nmcli connection modify WhatEverConnectionName ipv4.address "WhatEverIPAddress/SubnetMaskNumber" (192.168.1.1/24) | ||
*** nmcli connection up WhatEverConnectionName (essentially restarts the adapter and adopts new configuration information) | ***nmcli connection up WhatEverConnectionName (essentially restarts the adapter and adopts new configuration information) | ||
*** Does NOT work as one might think to 'reload' or restart a Network Adapter after configuration changes are made: nmcli connection reload | ***Does NOT work as one might think to 'reload' or restart a Network Adapter after configuration changes are made: nmcli connection reload | ||
*** nmcli connection show WhatEverConnectionName (ipv4.address = configured value AND IPV4.ADDRESS = "live / actual value") | ***nmcli connection show WhatEverConnectionName (ipv4.address = configured value AND IPV4.ADDRESS = "live / actual value") | ||
** systemctl restart NetworkManager | **systemctl restart NetworkManager | ||
* | * | ||
'''Tricks, Tips, and Other Useful Information (all of which applies to Rocky Linux 9, and others based on Red Hat)''' | '''Tricks, Tips, and Other Useful Information (all of which applies to Rocky Linux 9, and others based on Red Hat)''' | ||
*Rocky Linux 9 Network Configuration Files Directory: /etc/Network/Manager/system-connections (NOT /etc/sysconfig/network-scripts) | *Rocky Linux 9 Network Configuration Files Directory: /etc/Network/Manager/system-connections (NOT /etc/sysconfig/network-scripts) | ||
*Network Configuration: nm-connection-editor | *Network Configuration for Rocky Linux: nm-connection-editor | ||
*If a Bridged Network Adapter is configured for a Virtual Machine, it will show up in the Host Machine as: vnet1, etc. | *If a Bridged Network Adapter is configured for a Virtual Machine, it will show up in the Host Machine as: vnet1, etc. | ||
*QEMU / KVM Bridges can be configure "within" QEMU / KVM and "externally" using commands like brctl, etc. | |||
*QEMU / KVM Configuration Files: /etc/libvirt/qemu/ | *QEMU / KVM Configuration Files: /etc/libvirt/qemu/ | ||
**Heed the warning notes on some of these files as they should not be edited directly. Although a workaround is to edit the files directly, then restart the libvirtd.service (systemctl restart libvirtd.service) | **Heed the warning notes on some of these files as they should not be edited directly. Although a workaround is to edit the files directly, then restart the libvirtd.service (systemctl restart libvirtd.service) | ||
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Why is the UUID for the virbr0 Virtual Bridge Adapter displayed in the QEMU / KVM Host using the IP LINK SHOW command different than the UUID setting configured in the /etc/libvirt/qemu/networks/default.xml File, even though the MAC Address is the same in the Host (using IP LINK SHOW) and the default.xml File? | Why is the UUID for the virbr0 Virtual Bridge Adapter displayed in the QEMU / KVM Host using the IP LINK SHOW command different than the UUID setting configured in the /etc/libvirt/qemu/networks/default.xml File, even though the MAC Address is the same in the Host (using IP LINK SHOW) and the default.xml File? | ||
ChatGPT's explanation is below | ChatGPT's explanation is below (which is very good considering that Googling an equivalent answer produces nothing but hundreds of stupid forum results that ramble about how something isn't working). There is also some additional information from https://wiki.libvirt.org/Networking.html.<syntaxhighlight lang="text"> | ||
The discrepancy between the UUID in the default.xml file and the one displayed by the ip link show command might be due to the fact that the UUID in the XML configuration file refers to the libvirt network object's UUID, not the actual bridge interface's UUID. | The discrepancy between the UUID in the default.xml file and the one displayed by the ip link show command might be due to the fact that the UUID in the XML configuration file refers to the libvirt network object's UUID, not the actual bridge interface's UUID. | ||
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</syntaxhighlight> | </syntaxhighlight> | ||
The above can be confirmed using the following commands | |||
* virsh net-destroy default (maybe there should be an 'in-between' option like net-stop, but oh well) : "Stops and Destroys" the virbr0 (defined by default.xml, which is not deleted) | |||
* virsh net-start default : Starts the virb0 (defined by the default.xml file) | |||
* | |||
'''Rough Notes''' | |||
<network> | |||
<name>my-bridge-network</name> | |||
<forward mode='bridge'/> | |||
<bridge name='virbr_bridge'/> | |||
</network> | |||
sudo virsh net-define bridge-network.xml | |||
sudo virsh net-start my-bridge-network | |||
sudo virsh net-autostart my-bridge-network | |||
<syntaxhighlight lang="text"> | |||
virsh [options]... [<command_string>] | |||
virsh [options]... <command> [args...] | |||
options: | |||
-c | --connect=URI hypervisor connection URI | |||
-d | --debug=NUM debug level [0-4] | |||
-e | --escape <char> set escape sequence for console | |||
-h | --help this help | |||
-k | --keepalive-interval=NUM | |||
keepalive interval in seconds, 0 for disable | |||
-K | --keepalive-count=NUM | |||
number of possible missed keepalive messages | |||
-l | --log=FILE output logging to file | |||
-q | --quiet quiet mode | |||
-r | --readonly connect readonly | |||
-t | --timing print timing information | |||
-v short version | |||
-V long version | |||
--version[=TYPE] version, TYPE is short or long (default short) | |||
commands (non interactive mode): | |||
Domain Management (help keyword 'domain') | |||
attach-device attach device from an XML file | |||
attach-disk attach disk device | |||
attach-interface attach network interface | |||
autostart autostart a domain | |||
blkdeviotune Set or query a block device I/O tuning parameters. | |||
blkiotune Get or set blkio parameters | |||
blockcommit Start a block commit operation. | |||
blockcopy Start a block copy operation. | |||
blockjob Manage active block operations | |||
blockpull Populate a disk from its backing image. | |||
blockresize Resize block device of domain. | |||
change-media Change media of CD or floppy drive | |||
console connect to the guest console | |||
cpu-stats show domain cpu statistics | |||
create create a domain from an XML file | |||
define define (but don't start) a domain from an XML file | |||
desc show or set domain's description or title | |||
destroy destroy (stop) a domain | |||
detach-device detach device from an XML file | |||
detach-device-alias detach device from an alias | |||
detach-disk detach disk device | |||
detach-interface detach network interface | |||
domdisplay domain display connection URI | |||
domfsfreeze Freeze domain's mounted filesystems. | |||
domfsthaw Thaw domain's mounted filesystems. | |||
domfsinfo Get information of domain's mounted filesystems. | |||
domfstrim Invoke fstrim on domain's mounted filesystems. | |||
domhostname print the domain's hostname | |||
domid convert a domain name or UUID to domain id | |||
domif-setlink set link state of a virtual interface | |||
domiftune get/set parameters of a virtual interface | |||
domjobabort abort active domain job | |||
domjobinfo domain job information | |||
domlaunchsecinfo Get domain launch security info | |||
domsetlaunchsecstate Set domain launch security state | |||
domname convert a domain id or UUID to domain name | |||
domrename rename a domain | |||
dompmsuspend suspend a domain gracefully using power management functions | |||
dompmwakeup wakeup a domain from pmsuspended state | |||
domuuid convert a domain name or id to domain UUID | |||
domxml-from-native Convert native config to domain XML | |||
domxml-to-native Convert domain XML to native config | |||
dump dump the core of a domain to a file for analysis | |||
dumpxml domain information in XML | |||
edit edit XML configuration for a domain | |||
get-user-sshkeys list authorized SSH keys for given user (via agent) | |||
inject-nmi Inject NMI to the guest | |||
iothreadinfo view domain IOThreads | |||
iothreadpin control domain IOThread affinity | |||
iothreadadd add an IOThread to the guest domain | |||
iothreadset modifies an existing IOThread of the guest domain | |||
iothreaddel delete an IOThread from the guest domain | |||
send-key Send keycodes to the guest | |||
send-process-signal Send signals to processes | |||
lxc-enter-namespace LXC Guest Enter Namespace | |||
managedsave managed save of a domain state | |||
managedsave-remove Remove managed save of a domain | |||
managedsave-edit edit XML for a domain's managed save state file | |||
managedsave-dumpxml Domain information of managed save state file in XML | |||
managedsave-define redefine the XML for a domain's managed save state file | |||
memtune Get or set memory parameters | |||
perf Get or set perf event | |||
metadata show or set domain's custom XML metadata | |||
migrate migrate domain to another host | |||
migrate-setmaxdowntime set maximum tolerable downtime | |||
migrate-getmaxdowntime get maximum tolerable downtime | |||
migrate-compcache get/set compression cache size | |||
migrate-setspeed Set the maximum migration bandwidth | |||
migrate-getspeed Get the maximum migration bandwidth | |||
migrate-postcopy Switch running migration from pre-copy to post-copy | |||
numatune Get or set numa parameters | |||
qemu-attach QEMU Attach | |||
qemu-monitor-command QEMU Monitor Command | |||
qemu-monitor-event QEMU Monitor Events | |||
qemu-agent-command QEMU Guest Agent Command | |||
guest-agent-timeout Set the guest agent timeout | |||
reboot reboot a domain | |||
reset reset a domain | |||
restore restore a domain from a saved state in a file | |||
resume resume a domain | |||
save save a domain state to a file | |||
save-image-define redefine the XML for a domain's saved state file | |||
save-image-dumpxml saved state domain information in XML | |||
save-image-edit edit XML for a domain's saved state file | |||
schedinfo show/set scheduler parameters | |||
screenshot take a screenshot of a current domain console and store it into a file | |||
set-lifecycle-action change lifecycle actions | |||
set-user-sshkeys manipulate authorized SSH keys file for given user (via agent) | |||
set-user-password set the user password inside the domain | |||
setmaxmem change maximum memory limit | |||
setmem change memory allocation | |||
setvcpus change number of virtual CPUs | |||
shutdown gracefully shutdown a domain | |||
start start a (previously defined) inactive domain | |||
suspend suspend a domain | |||
ttyconsole tty console | |||
undefine undefine a domain | |||
update-device update device from an XML file | |||
update-memory-device update memory device of a domain | |||
vcpucount domain vcpu counts | |||
vcpuinfo detailed domain vcpu information | |||
vcpupin control or query domain vcpu affinity | |||
emulatorpin control or query domain emulator affinity | |||
vncdisplay vnc display | |||
guestvcpus query or modify state of vcpu in the guest (via agent) | |||
setvcpu attach/detach vcpu or groups of threads | |||
domblkthreshold set the threshold for block-threshold event for a given block device or it's backing chain element | |||
guestinfo query information about the guest (via agent) | |||
domdirtyrate-calc Calculate a vm's memory dirty rate | |||
dom-fd-associate associate a FD with a domain | |||
Domain Monitoring (help keyword 'monitor') | |||
domblkerror Show errors on block devices | |||
domblkinfo domain block device size information | |||
domblklist list all domain blocks | |||
domblkstat get device block stats for a domain | |||
domcontrol domain control interface state | |||
domif-getlink get link state of a virtual interface | |||
domifaddr Get network interfaces' addresses for a running domain | |||
domiflist list all domain virtual interfaces | |||
domifstat get network interface stats for a domain | |||
dominfo domain information | |||
dommemstat get memory statistics for a domain | |||
domstate domain state | |||
domstats get statistics about one or multiple domains | |||
domtime domain time | |||
list list domains | |||
Domain Events (help keyword 'events') | |||
event Domain Events | |||
Host and Hypervisor (help keyword 'host') | |||
allocpages Manipulate pages pool size | |||
capabilities capabilities | |||
cpu-baseline compute baseline CPU | |||
cpu-compare compare host CPU with a CPU described by an XML file | |||
cpu-models CPU models | |||
domcapabilities domain capabilities | |||
freecell NUMA free memory | |||
freepages NUMA free pages | |||
hostname print the hypervisor hostname | |||
hypervisor-cpu-baseline compute baseline CPU usable by a specific hypervisor | |||
hypervisor-cpu-compare compare a CPU with the CPU created by a hypervisor on the host | |||
maxvcpus connection vcpu maximum | |||
node-memory-tune Get or set node memory parameters | |||
nodecpumap node cpu map | |||
nodecpustats Prints cpu stats of the node. | |||
nodeinfo node information | |||
nodememstats Prints memory stats of the node. | |||
nodesevinfo node SEV information | |||
nodesuspend suspend the host node for a given time duration | |||
sysinfo print the hypervisor sysinfo | |||
uri print the hypervisor canonical URI | |||
version show version | |||
Checkpoint (help keyword 'checkpoint') | |||
checkpoint-create Create a checkpoint from XML | |||
checkpoint-create-as Create a checkpoint from a set of args | |||
checkpoint-delete Delete a domain checkpoint | |||
checkpoint-dumpxml Dump XML for a domain checkpoint | |||
checkpoint-edit edit XML for a checkpoint | |||
checkpoint-info checkpoint information | |||
checkpoint-list List checkpoints for a domain | |||
checkpoint-parent Get the name of the parent of a checkpoint | |||
Interface (help keyword 'interface') | |||
iface-begin create a snapshot of current interfaces settings, which can be later committed (iface-commit) or restored (iface-rollback) | |||
iface-bridge create a bridge device and attach an existing network device to it | |||
iface-commit commit changes made since iface-begin and free restore point | |||
iface-define define an inactive persistent physical host interface or modify an existing persistent one from an XML file | |||
iface-destroy destroy a physical host interface (disable it / "if-down") | |||
iface-dumpxml interface information in XML | |||
iface-edit edit XML configuration for a physical host interface | |||
iface-list list physical host interfaces | |||
iface-mac convert an interface name to interface MAC address | |||
iface-name convert an interface MAC address to interface name | |||
iface-rollback rollback to previous saved configuration created via iface-begin | |||
iface-start start a physical host interface (enable it / "if-up") | |||
iface-unbridge undefine a bridge device after detaching its device(s) | |||
iface-undefine undefine a physical host interface (remove it from configuration) | |||
Network Filter (help keyword 'filter') | |||
nwfilter-define define or update a network filter from an XML file | |||
nwfilter-dumpxml network filter information in XML | |||
nwfilter-edit edit XML configuration for a network filter | |||
nwfilter-list list network filters | |||
nwfilter-undefine undefine a network filter | |||
nwfilter-binding-create create a network filter binding from an XML file | |||
nwfilter-binding-delete delete a network filter binding | |||
nwfilter-binding-dumpxml network filter information in XML | |||
nwfilter-binding-list list network filter bindings | |||
Networking (help keyword 'network') | |||
net-autostart autostart a network | |||
net-create create a network from an XML file | |||
net-define define an inactive persistent virtual network or modify an existing persistent one from an XML file | |||
net-destroy destroy (stop) a network | |||
net-dhcp-leases print lease info for a given network | |||
net-dumpxml network information in XML | |||
net-edit edit XML configuration for a network | |||
net-event Network Events | |||
net-info network information | |||
net-list list networks | |||
net-name convert a network UUID to network name | |||
net-start start a (previously defined) inactive network | |||
net-undefine undefine a persistent network | |||
net-update update parts of an existing network's configuration | |||
net-uuid convert a network name to network UUID | |||
net-port-list list network ports | |||
net-port-create create a network port from an XML file | |||
net-port-dumpxml network port information in XML | |||
net-port-delete delete the specified network port | |||
Node Device (help keyword 'nodedev') | |||
nodedev-create create a device defined by an XML file on the node | |||
nodedev-destroy destroy (stop) a device on the node | |||
nodedev-detach detach node device from its device driver | |||
nodedev-dumpxml node device details in XML | |||
nodedev-list enumerate devices on this host | |||
nodedev-reattach reattach node device to its device driver | |||
nodedev-reset reset node device | |||
nodedev-event Node Device Events | |||
nodedev-define Define a device by an xml file on a node | |||
nodedev-undefine Undefine an inactive node device | |||
nodedev-start Start an inactive node device | |||
nodedev-autostart autostart a defined node device | |||
nodedev-info node device information | |||
Secret (help keyword 'secret') | |||
secret-define define or modify a secret from an XML file | |||
secret-dumpxml secret attributes in XML | |||
secret-event Secret Events | |||
secret-get-value Output a secret value | |||
secret-list list secrets | |||
secret-set-value set a secret value | |||
secret-undefine undefine a secret | |||
Snapshot (help keyword 'snapshot') | |||
snapshot-create Create a snapshot from XML | |||
snapshot-create-as Create a snapshot from a set of args | |||
snapshot-current Get or set the current snapshot | |||
snapshot-delete Delete a domain snapshot | |||
snapshot-dumpxml Dump XML for a domain snapshot | |||
snapshot-edit edit XML for a snapshot | |||
snapshot-info snapshot information | |||
snapshot-list List snapshots for a domain | |||
snapshot-parent Get the name of the parent of a snapshot | |||
snapshot-revert Revert a domain to a snapshot | |||
Backup (help keyword 'backup') | |||
backup-begin Start a disk backup of a live domain | |||
backup-dumpxml Dump XML for an ongoing domain block backup job | |||
Storage Pool (help keyword 'pool') | |||
find-storage-pool-sources-as find potential storage pool sources | |||
find-storage-pool-sources discover potential storage pool sources | |||
pool-autostart autostart a pool | |||
pool-build build a pool | |||
pool-create-as create a pool from a set of args | |||
pool-create create a pool from an XML file | |||
pool-define-as define a pool from a set of args | |||
pool-define define an inactive persistent storage pool or modify an existing persistent one from an XML file | |||
pool-delete delete a pool | |||
pool-destroy destroy (stop) a pool | |||
pool-dumpxml pool information in XML | |||
pool-edit edit XML configuration for a storage pool | |||
pool-info storage pool information | |||
pool-list list pools | |||
pool-name convert a pool UUID to pool name | |||
pool-refresh refresh a pool | |||
pool-start start a (previously defined) inactive pool | |||
pool-undefine undefine an inactive pool | |||
pool-uuid convert a pool name to pool UUID | |||
pool-event Storage Pool Events | |||
pool-capabilities storage pool capabilities | |||
Storage Volume (help keyword 'volume') | |||
vol-clone clone a volume. | |||
vol-create-as create a volume from a set of args | |||
vol-create create a vol from an XML file | |||
vol-create-from create a vol, using another volume as input | |||
vol-delete delete a vol | |||
vol-download download volume contents to a file | |||
vol-dumpxml vol information in XML | |||
vol-info storage vol information | |||
vol-key returns the volume key for a given volume name or path | |||
vol-list list vols | |||
vol-name returns the volume name for a given volume key or path | |||
vol-path returns the volume path for a given volume name or key | |||
vol-pool returns the storage pool for a given volume key or path | |||
vol-resize resize a vol | |||
vol-upload upload file contents to a volume | |||
vol-wipe wipe a vol | |||
Virsh itself (help keyword 'virsh') | |||
cd change the current directory | |||
echo echo arguments. Used for internal testing. | |||
exit quit this interactive terminal | |||
help print help | |||
pwd print the current directory | |||
quit quit this interactive terminal | |||
connect (re)connect to hypervisor | |||
(specify help <group> for details about the commands in the group) | |||
(specify help <command> for details about the command) | |||
</syntaxhighlight> | |||